Ideally, I would like to edit my own comment, but that's probably not in the cards. But then at least I should be able to hide it, but clicking on Moderator View only the three other comments appear, my own is not there...
If you're logged into Facebook with the user that posted the comment, you can hover your mouse over the post and there should be a pencil icon on the right. From there, you can select to edit or delete the comment.